I've opened up the repo now (https://github.com/CoreyGinnivan/system-uicons), the licence is officially "Unlicense License" - it's all public domain. The SVGs are all in the repo (or can download on the site). I'll be releasing Sketch and Figma files soon :)

I'm curious about reasons you chose Unlicense

I like the icons, especially the bells, look cleaner than other fonts, to me

Thanks! I chose it because I want it to be public domain, people can copy, remake, improve, do whatever they want with it. Don't having to worry about any infringements.

Thank you!

Bottom of the page says:

""Use how you want, without attribution""

And they are SVG, the display is the source.